Flask



FIG. 1 is a top, front and right side perspective view of a flaskembodying my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a front elevational view thereof, the rear elevational viewbeing identical; and,

FIG. 4 is a right side elevational view thereof, the left sideelevational view being identical.

The ornamental design for a flask, as shown and described.